Photographing interference detection device

Abstract

To reduce the time required for detection of photographing interference of a preset position that is previously registered.SOLUTION: A photographing interference detection device 100 that detects photographing interference of a camera unit 20, comprises a detection part 314 that is provided to a calculation part of a microcontroller 310. The camera unit 20 performs an auto focus operation when a photographing position of the camera unit 20 is switched to preset positions 72 to 74 that are previously registered. The detection part 314 outputs a detection signal that indicates detection of the photographing interference of the preset positions 72 to 74 in the case where a focal point of a lens block 21 after the auto focus operation of the camera unit 20 is moved to a position deviated from a reference focal point position.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a photography tampering detection device. [Background technology]

[0002] Patent Document 1 proposes a technique for calculating the luminance difference between an image captured by a surveillance camera and a reference image for each pixel, and determining whether or not camera tampering has occurred based on the number of changed pixels for which the luminance difference is greater than a first threshold value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-77517 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of Patent Document 1 requires image processing to calculate the brightness difference between the image of the surveillance camera and the reference image in order to determine whether or not there is camera tampering, which takes time to make the determination. The present invention aims to shorten the time it takes to detect tampering with photography at a preset position that has been registered in advance. [Means for solving the problem]

[0005] In order to achieve the above object, a shooting tampering detection device according to one aspect of the present invention comprises: A device for detecting interference with photography of a camera performing an autofocus operation, comprising: The camera is provided with a detection unit that outputs a detection signal indicating that obstruction of photography at a preset position has been detected when the autofocus operation when the photography position of the camera is switched to a preregistered preset position causes the focus of the camera to move to a position away from the reference focus position of the preset position. Effect of the Invention

[0006] According to the present invention, it is possible to reduce the time required to detect interference with photography at a preset position that has been registered in advance. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an outline of the configuration of a surveillance camera device equipped with a shooting tampering detection device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of setting of preset positions by the camera unit of FIG. [Diagram 3] FIG. 3 is a diagram showing shooting information registered for the preset positions in FIG. [Figure 4] FIG. 4 is a flowchart illustrating an example of a processing procedure executed in the photography tampering detection device of FIG. [Diagram 5] FIG. 5 is a diagram showing an example of the relationship between possible patterns of imaging interference in the surveillance camera device of FIG. 1 and events occurring in each pattern. [Figure 6] FIG. 6 is a diagram showing an example of a state in which one of the preset positions in FIG. 2 is blocked from the field of view of the lens block by an obstruction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same or equivalent parts or components are designated by the same reference numerals throughout the drawings.

[0009] The following embodiments are examples of devices and the like for embodying the technical idea of ​​the present invention. The technical idea of ​​the present invention does not limit the materials, shapes, structures, arrangements, etc. of each component part to those described below.

[0010] 1, a photography tampering detection device 100 of this embodiment is provided in a surveillance camera device 10 that outputs a photographed image of a monitored space (not shown). The surveillance camera device 10 has a camera unit 20 and a controller 30. The photography tampering detection device can be configured using, for example, the controller 30.

[0011] The camera unit 20 is installed, for example, at a high place in the monitored space. The high place may be, for example, the ceiling of the monitored space. The camera unit 20 may be, for example, a PTZ (Pan-Tilt-Zoom) camera with a built-in tilt mechanism and pan mechanism (neither shown) that change the shooting direction up, down, left, and right. The camera unit 20 has a lens block 21, a zoom adjustment unit 22, a focus adjustment unit 23, and an imaging unit 24.

[0012] The lens block 21 has a lens group made up of a plurality of lenses. Each lens constituting the lens group can move in the direction of its respective lens optical axis. The zoom adjustment unit 22 and the focus adjustment unit 23 move each lens of the lens group individually in the direction of the lens optical axis to optically adjust the zoom position of the lens block 21 and the focus of the lens block 21, which correspond to the magnification of the image of the subject, respectively.

[0013] The imaging unit 24 is an image sensor having a solid-state imaging element. For example, a CMOS (Complementary Metal-Oxide-Semiconductor) or a CCD (Charge-Coupled Device) can be used as the solid-state imaging element. An image is formed on the imaging unit 24 by light passing through the lens block 21. The imaging unit 24 photoelectrically converts the light of the image formed on the imaging unit 24, and outputs an image signal that is an electrical signal of the image formed on the imaging unit 24.

[0014] The camera unit 20 can perform patrol photography by sequentially switching the photographing position among a plurality of preset positions. In addition to patrol photography, the camera unit 20 can perform photography at any position desired by the user, for example, by operating an operation panel (not shown). After photographing an arbitrary position with the camera unit 20 by the user's operation, if the original photographing position is registered as a preset position, the photographing position of the camera unit 20 can be returned to the original position. The preset positions of the camera unit 20 can be registered in advance. FIG. 2 shows a case where three gates 62 to 64 provided on a wall 61 of a logistics warehouse 60, which is a monitored space, are set as preset positions 72 to 74. In this example, the camera unit 20 is installed on the ceiling 65 of the logistics warehouse 60.

[0015] 3 shows shooting information by the camera unit 20 that is registered in advance for each of the preset positions 72 to 74. The shooting information of the registered preset positions 72 to 74 can be stored, for example, in a storage device 320 (described later) of the controller 30. For example, when the camera unit 20 is a PTZ camera, parameters of "Pan," "Tilt," and "Zoom" are registered in the storage device 320 as the shooting information of the preset positions 72 to 74.

[0016] "Pan" is the left / right swing angle of camera unit 20 from a reference direction (not shown), "Tilt" is the up / down swing angle of camera unit 20 from the reference direction, both in degrees. "Zoom" is the optical zoom magnification of the subject by zoom lens 211.

[0017] The "Focus" parameter is initially set for each of the preset positions 72 to 74 in which the "Pan", "Tilt", and "Zoom" parameters are registered as shooting information. "Focus" is the distance from the principal point of the lens block 21 to the focal point, measured in millimeters (mm). The principal point of the lens block 21 is the center point of a lens when the lens block 21 is replaced with an optically equivalent lens. In the initial setting of the "Focus" parameter, the camera unit 20 photographs each of the preset positions 72 to 74 with the registered "Pan", "Tilt", and "Zoom" parameters, and performs an autofocus operation. When photographing each of the preset positions 72 to 74 in the state shown in FIG. 2 in order to set the "Focus" parameter, the lens block 21 focuses on each of the gates 62 to 64 by the autofocus operation performed by the camera unit 20. The focus of the lens block 21 at this time is an initial setting value in the shooting information of each of the preset positions 72 to 74, that is, a reference focus position, and is registered in the storage device 320 as "Focus" together with the parameters of "Pan", "Tilt", and "Zoom". The registered reference focus positions ("Focus") of each of the preset positions 72 to 74 can be used, for example, to detect shooting interference with the surveillance camera device 10. Shooting interference with the surveillance camera device 10 can be detected, for example, based on whether the focus of the lens block 21 during shooting at each of the preset positions 72 to 74 has changed from the reference focus position. Whether the focus of the lens block 21 has changed from the reference focus position can be determined by comparing the focus of the lens block 21 after the autofocus operation with "Focus", that is, the reference focus position, during shooting at each of the preset positions 72 to 74. The position of the focus is also called the focus position.

[0018] In the example shown in FIG. 3, "Focus Range" is added to the shooting information of the preset positions 72 to 74. The focus of the lens block 21 may shift slightly due to, for example, vibration of the camera unit 20, changes in shooting conditions such as lighting, even if the object to be shot by the camera unit 20 does not change. "Focus Range" indicates the allowable range of the focus shift of the lens block 21 from the reference focus position when determining whether the focus of the lens block 21 at the time of shooting the preset positions 72 to 74 has changed from the reference focus position. For example, if the focus of the lens block 21 at the time of shooting is within the range of "Focus Range", it can be determined that the focus of the lens block 21 at the time of shooting is "Focus", that is, has not changed from the reference focus position. The unit of "Focus Range" is millimeters (mm). For example, if the change in focus when the camera unit 20 focuses on an entering / leaving vehicle (not shown) passing through the gates 62 to 64 is not considered to be an obstruction to shooting, the "Focus Range" may be set to a wide range. By setting the "Focus Range" to a wide range, even if the focus of the lens block 21 at the time of photographing at each of the preset positions 72 to 74 shifts to the position of an entering or leaving vehicle, it is possible to prevent the shift from being determined as a photographing obstruction. As shown in FIG. 3, at the preset position 74, the "Focus", i.e., the reference focus position, is 80 (mm). For example, if the focus of the lens block 21 at the time of photographing changes to 70 (mm) due to a vehicle entering or leaving the gate 64, since 70 (mm) is within the "Focus Range", it is not determined that the focus of the lens block 21 at the time of photographing has changed from the reference focus position. If the "Focus Range" is set to a range that does not include the focus when the camera unit 20 is covered with a cloth, for example, the change in focus of the lens block 21 at the time of photographing due to the cloth being covered can be determined to be a change from the reference focus position, and photographing obstruction can be detected.

[0019] As shown in FIG. 1, the controller 30 has a general-purpose microcontroller 310 and a storage device 320. The storage device 320 can be configured, for example, by an SSD (Solid State Drive) or an HDD (Hard Disk Drive). The microcontroller 310 includes a CPU (Central Processing Unit) and a memory. The memory includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The microcontroller 310 can virtually configure a plurality of information processing circuits by, for example, executing a program stored in the memory by the CPU. The plurality of information processing circuits can configure an input / output unit and an arithmetic unit of the microcontroller 310.

[0020] The input / output unit can acquire, for example, an image signal output by the imaging unit 24. The input / output unit can output, for example, an image signal when the camera unit 20 captures an image at a shooting position including the preset positions 72 to 74 to a display (not shown). The calculation unit can configure a shooting target switching unit 311, an autofocus processing unit 312, a focus position determination unit 313, a detection unit 314, and a notification unit 315, which will be described later, of the microcontroller 310. The shooting interference detection device 100 according to this embodiment can be configured to include the detection unit 314, and may further include the notification unit 315.

[0021] In this embodiment, an example is shown in which multiple information processing circuits built in the microcontroller 310 are realized by software. Of course, it is also possible to prepare dedicated hardware for executing each information processing of the input / output unit and the arithmetic unit to configure the information processing circuits. Also, the multiple information processing circuits may be configured by individual hardware. The dedicated hardware includes devices such as application specific integrated circuits (ASICs) and conventional circuit components arranged to execute the functions of the input / output unit and the arithmetic unit.

[0022] The photographing position switching unit 311 switches the photographing position of the camera unit 20. When the photographing position switching unit 311 performs patrol photographing with the camera unit 20, the photographing position switching unit 311 sequentially switches the camera unit 20 to the orientation and zoom magnification corresponding to each parameter of "Pan", "Tilt", and "Zoom" of the preset positions 72 to 74 stored in the storage device 320. When the photographing position switching unit 311 photographs an arbitrary position desired by the user with the camera unit 20, the photographing position switching unit 311 switches the camera unit 20 to the orientation and zoom magnification corresponding to the user's operation. The photographing position can be switched by operating a tilt mechanism and a pan mechanism (not shown) of the camera unit 20 and the zoom adjustment unit 22. When patrol photographing is performed, the photographing position can be switched at regular intervals, for example.

[0023] The autofocus processing unit 312 executes an autofocus operation of the camera unit 20, for example, when the shooting position of the camera unit 20 is switched by patrol shooting or a user operation. In this embodiment, the autofocus processing unit 312 performs autofocus processing that does not require image processing. The autofocus processing that does not require image processing may be, for example, phase difference autofocus processing or laser autofocus processing. In this embodiment, a case where phase difference autofocus is used will be described.

[0024] In the phase difference autofocus process, the autofocus processor 312 detects the phase difference between two images formed on the imaging unit 24 by the light passing through the lens block 21. The two images for which the phase difference is detected may be two images formed on separate imaging elements of the imaging unit 24 by splitting the light passing through the lens block 21 into two by a beam splitter. The two images for which the phase difference is detected may be two images formed on an AF (Auto Focus) sensor arranged on a single imaging element of the imaging unit 24 by splitting the light passing through the lens block 21 into two by a separator lens (not shown). In the latter case, the phase difference between the two images is the image plane phase difference obtained from the output of the AF sensor. The autofocus processor 312 detects pixel shift between the two images based on the detected phase difference, and detects the amount and direction of focus shift of the lens block 21 from the detected pixel shift.

[0025] The autofocus processing unit 312 executes an autofocus operation of the camera unit 20 based on the detected amount of focus deviation. In the autofocus operation, the autofocus processing unit 312 moves each lens of the lens block 21 in the direction of the optical axis of each lens by the zoom adjustment unit 22 and the focus adjustment unit 23 so as to eliminate the amount of focus deviation. The autofocus processing unit 312 stops the movement of each lens at a position where the amount of focus deviation is eliminated, and completes the autofocus operation of the camera unit 20. The focus of the lens block 21 when the autofocus operation is completed becomes the position of the subject focused on when photographing at the photographing position.

[0026] The autofocus processing unit 312 normally ends the autofocus operation if the autofocus operation is completed within a predetermined time from the start of the autofocus operation, and abnormally ends the autofocus operation if the autofocus operation is not completed within a predetermined time from the start of the autofocus operation.

[0027] The focus position determination unit 313 determines the focal position of the lens block 21 from the movement amount of each lens of the lens block 21 when the autofocus operation is normally completed. The focus position determination unit 313 may store the determined focal position of the lens block 21 in, for example, a memory of the microcontroller 310 as the focal position after the autofocus operation. The focus position determination unit 313 can determine whether the determined focal position of the lens block 21 has deviated to either near or far from the reference focal position of the preset positions 72 to 74 that are the shooting positions during the autofocus operation. The focus position determination unit 313 may determine whether the focal position of the lens block 21 after the autofocus operation has deviated from the reference focal position by using the upper limit value and the lower limit value of the "Focus Range" of the preset positions 72 to 74 in FIG. 3 as threshold values. The focus position determination unit 313 may determine whether the focal position of the lens block 21 deviated from the reference focal position of the preset positions 72 to 74 has deviated to either near or far.

[0028] The detection unit 314 outputs a detection signal indicating detection of interference with photography when the focus position determination unit 313 determines that the focus of the lens block 21 after the autofocus operation when the photography position is switched to the preset positions 72 to 74 has deviated from the reference focus position. The detection unit 314 may output the detection signal based on the determination result of whether the position deviated from the reference focus position of the preset positions 72 to 74 is closer to the lens block 21 or farther from the lens block 21 than the reference focus position.

[0029] The detection unit 314 may be configured to output a detection signal of interference with photography only when the focus position determination unit 313 determines that the focus of the lens block 21 after the autofocus operation has deviated to the near side closer to the camera unit 20 than the reference focus position. The focal length of the lens block 21 that has defocused to the near side from the reference focus position after the autofocus operation at the preset positions 72 to 74 is shorter than the lower limit of the "Focus Range" of the preset positions 72 to 74. The detection unit 314 regards this state as a state in which an obstruction that obstructs the photography of the gates 62 to 64 has appeared between the gates 62 to 64 that are originally to be photographed during photography at the preset positions 72 to 74 and the camera unit 20. The position deviated to the near side from the reference focus position may be determined, for example, by whether or not the focus is closer to the camera unit 20 than the adjustable range of the focus corresponding to the registered "Zoom" parameter of the preset positions 72 to 74 that are the photography positions. If the focal point of lens block 21 is within the adjustable range, then the focal point can be considered to be substantially located at a position within the "Focus Range" of preset positions 72 to 74 that are set as shooting positions.

[0030] The detection unit 314 may be configured to output a detection signal of photography interference only when the focus of the lens block 21 after the autofocus operation deviates from the reference focus position of the subject to be photographed during autofocus, for example, only when the autofocus operation ends abnormally. The detection unit 314 may be configured to output a different detection signal in each of the following cases: when the focus of the lens block 21 after the autofocus operation deviates from the reference focus position, when the focus deviates from the reference focus position to the near side, and when the autofocus operation ends abnormally.

[0031] Based on the detection signal output by the detection unit 314, the notification unit 315 outputs a notification signal to notify the user that shooting by the camera units 20 at the preset positions 72 to 74 has been obstructed.

[0032] Next, an example of a processing procedure executed by the photography interference detection device 100 to detect a state in which photography at preset positions 72 to 74 by the camera unit 20 in the surveillance camera device 10 of this embodiment is interfered with will be described with reference to Fig. 4. The photography interference detection device 100 repeatedly executes the processing procedure exemplified in Fig. 4 while the surveillance camera device 10 is in operation. The processing procedure in Fig. 4 is an example of detecting photography interference when the focus of the lens block 21 after an autofocus operation has shifted to the near side from the reference focus position.

[0033] First, when the photographing position of the camera unit 20 is switched to one of the preset positions 72 to 74 (step S101), the detection unit 314 instructs the autofocus processing unit 312 to execute the autofocus operation of the camera unit 20 (step S102). The detection unit 314 checks whether the autofocus operation executed by the autofocus processing unit 312 has been completed normally (step S103). If the autofocus operation has not been completed normally but has been abnormally completed (NO in step S103), the process proceeds to step S105 described later. If the autofocus operation has been completed normally (YES in step S103), the detection unit 314 checks whether the focus of the lens block 21 determined by the focus position determination unit 313 after the autofocus operation has shifted to the near side (step S104). The detection unit 314 checks whether the focus of the lens block 21 after the autofocus operation has shifted to the near side based on the reference focus positions of the preset positions 72 to 74 corresponding to the photographing positions of the camera unit 20.

[0034] The detection unit 314 may confirm that the focus has shifted from the reference focus position to the near side, for example, when the focal length of the lens block 21 after the autofocus operation is shorter than the lower limit value of the "Focus Range" registered in the shooting position preset positions 72 to 74. The detection unit 314 may confirm that the focus has shifted from the reference focus position to the near side, when the focal length of the lens block 21 is shorter than the lower limit value of the focus adjustable range corresponding to the "Zoom" parameter registered in the shooting position preset positions 72 to 74.

[0035] If the focus of the lens block 21 after the autofocus operation has not shifted from the reference focus position to the near side (NO in step S104), the series of procedures ends. If the focus after the autofocus operation has shifted from the reference focus position to the near side (YES in step S104), the process proceeds to step S105.

[0036] In step S105, the detection unit 314 outputs a detection signal. The notification unit 315 outputs a notification signal based on the detection signal output by the detection unit 314 (step S106). After the notification unit 315 outputs the notification signal, the series of procedures ends.

[0037] Fig. 5 shows an example of the relationship between possible patterns of photography interference in the surveillance camera device 10 and events occurring in each pattern. In the surveillance camera device 10, scenes in which photography at preset positions 72 to 74 is interfered with include, for example, scenes shown in the leftmost column of Fig. 5.

[0038] Of these, in the "obstruction" scene, as shown in the rightmost column of Fig. 5, the focal point of lens block 21 is on the near side of the reference focal position of preset positions 72 to 74. The near side means the side closer to camera unit 20 than the reference focal position. In the "moving subject farther away" scene, the focal point of lens block 21 after autofocus operation is on the far side of the reference focal position. The far side means the side opposite to camera unit 20 than the reference focal position.

[0039] In each of the scenes of "half of the lens is sprayed" and "strong light hits half of the lens", the focus of the lens block 21 after the autofocus operation is nearer or farther than the reference focus position of the preset positions 72 to 74. In the scene of "the camera direction changes", the focus of the lens block 21 after the autofocus operation is nearer or farther than the reference focus position of the preset positions 72 to 74. Alternatively, the autofocus operation may end abnormally because a focusable subject cannot be identified, and the focus of the lens block 21 after the autofocus operation may become unpredictable. In each of the scenes of "the lens is covered with a cloth", "the entire lens is sprayed", and "strong light hits the entire lens", the autofocus operation may end abnormally and the focus of the lens block 21 after the autofocus operation may become unpredictable.

[0040] An "obstruction" refers to an object that exists between the reference focal positions of preset positions 72 to 74 and the camera unit 20 and blocks the field of view of the lens block 21 in front of the reference focal position. FIG. 6 shows a state in which a part of the gate 64 is blocked from the field of view of the lens block 21 by a vehicle 80 in the logistics warehouse 60 when the shooting position is preset position 74. In this case, the vehicle 80 corresponds to an "obstruction" that prevents the camera unit 20 from shooting the gate 64.

[0041] If shooting of a subject such as gates 62-64 of preset positions 72-74 is obstructed, it is expected that the focus of lens block 21 after autofocus operation will shift from the reference focus position. For example, in a scene where shooting of a subject is obstructed by an "obstruction," it is expected that the focus of lens block 21 after autofocus operation will move toward camera unit 20 from the reference focus position, as shown in FIG.

[0042] In this embodiment, after the autofocus operation when the photographing position of the camera unit 20 is switched to the preset positions 72 to 74, the detection unit 314 detects the focus of the lens block 21. This autofocus operation is performed as an operation to replace the position detection of the photographing target, in order to confirm through the focus of the lens block 21 whether the photographing target of the camera unit 20 has changed to an object closer to the camera unit 20 than the gates 62 to 64. In the autofocus operation, when the focus of the lens block 21 moves to the near side from the registered reference focus position, the focus of the lens block 21 is adjusted to an object located in front of the gates 62 to 64 of the preset positions 72 to 74. In this case, it is estimated that the photographing of the gates 62 to 64 that should have been photographed is obstructed, and the gates 62 to 64 are not photographed appropriately by the camera unit 20.

[0043] In the autofocus operation, when the focal point of the lens block 21 moves to a position deviating from the reference focal position, a detection signal and a notification signal of the photography sabotage are output by the detection unit 314 and the notification unit 315. The photography sabotage detection device 100 can recognize the occurrence of photography sabotage in a control manner by the detection signal. The photography sabotage detection device 100 can notify the user of the occurrence of photography sabotage by the notification signal.

[0044] In this embodiment, when the focal point of the lens block 21 moves closer to the near side than the reference focal position after the autofocus operation at the preset positions 72 to 74, the lens block 21 is focused on an object in front of the gates 62 to 64. In this case, it is assumed that an "obstruction" is present at a position closer to the camera unit 20 than the gates 62 to 64, which are the subjects of the image capture. If the autofocus operation does not end normally in the autofocus operation, it is presumed that the lens block 21 does not capture the subject of the image capture to be focused. In these states, it is considered that the field of view of the camera unit 20 is obstructed in front of the reference focal position or near the lens block 21.

[0045] In the autofocus operation, when the focal point of the lens block 21 moves to a position deviated from the reference focal position to the near side, the detection unit 314 and the notification unit 315 output a detection signal and a notification signal of shooting interference caused by an "obstruction". The shooting interference detection device 100 can recognize the occurrence of shooting interference caused by an "obstruction" in a control manner by the detection signal. The shooting interference detection device 100 can notify the user of the occurrence of shooting interference caused by an "obstruction" by the notification signal.

[0046] In this embodiment, if the autofocus operation at the preset positions 72 to 74 does not end normally, the detection unit 314 and the notification unit 315 output a detection signal and a notification signal of a shooting interference. The shooting interference detection device 100 can recognize, in a control manner, the occurrence of shooting interference caused by the lens block 21 not capturing a shooting target to be focused on, by the detection signal. The shooting interference detection device 100 can notify the user, by the notification signal, of the occurrence of shooting interference caused by the lens block 21 not capturing a shooting target to be focused on.

[0047] In this embodiment, when the focus of the lens block 21 deviates from the reference focus position to the near side after the autofocus operation, the user is notified of the occurrence of "photography interference due to an obstruction". Or, when the autofocus operation does not end normally, the user is notified of the occurrence of "photography interference due to not capturing the subject to be photographed". However, when the focus of the lens block 21 deviates from the reference focus position, including when the focus of the lens block 21 deviates from the reference focus position to the far side after the autofocus operation, the user may be notified that some kind of photography interference has occurred. Also, different notifications may be made in each of the following cases: when the focus of the lens block 21 deviates from the reference focus position to the near side, when the focus deviates from the reference focus position to the far side, and when the autofocus operation ends abnormally.

[0048] In this embodiment, the autofocus operation of the camera unit 20 is performed by phase-difference autofocus processing that does not require image processing, so the detection unit 314 can quickly detect the occurrence of photography sabotage from the relationship between the focus after the autofocus operation and the reference focus position. In the photography sabotage detection device 100 of this embodiment, the time it takes for the detection unit 314 to detect photography sabotage can be shortened.

[0049] In this embodiment, the photography sabotage detection device 100 is provided in the controller 30, but the photography sabotage detection device according to the present invention may be provided in a part other than the controller 30, such as a computer that communicates with the controller 30 via a network.

[0050] Although the embodiment of the present invention has been described above, the embodiment can be modified or changed based on the above disclosure. All the components of the above embodiment and all the features described in the claims may be individually extracted and combined as long as they are not mutually inconsistent. [Explanation of symbols]

[0051] 20 Camera unit (camera) 21 Lens block 72~74 Preset positions (shooting subject) 100 Filming tampering detection device 310 Microcontroller 314 Detection unit 315 Information Department

Claims

1. A device for detecting interference with photography of a camera performing an autofocus operation, comprising: a detection unit which outputs a detection signal indicating detection of obstruction of photography at the preset position when the autofocus operation when the photography position of the camera is switched to a preset position registered in advance causes the focus of the camera to move to a position deviated from a reference focus position of the preset position, Filming tampering detection device.

2. The photography interference detection device according to claim 1, wherein the detection unit outputs the detection signal based on a determination result of whether a position of the preset position that is out of the reference focal position is closer to the lens or farther from the lens than the reference focal position.

3. The photography interference detection device of claim 1, wherein the detection unit outputs the detection signal when a position of the preset position that is out of the reference focus position is closer to the lens than the adjustable range of focus corresponding to the optical zoom magnification of the image at the preset position.

4. The shooting interference detection device of claim 1, wherein the detection unit outputs the detection signal when it detects that the autofocus operation when the shooting position is switched to the preset position is not completed within a predetermined time from the start and terminates abnormally.

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